SpriteLibrary/SpriteLibrary/KeyMessageFilter.cs

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C#
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2017-09-03 03:35:32 +02:00
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace SpriteLibrary
{
/// <summary>
/// This is a delegate for a keypress event.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
public delegate void SpriteKeyEventHandler(object sender, KeyEventArgs e);
/// <summary>
/// This is a system that can be used to check for any keypress on a form. It is usually used through <see cref="SpriteLibrary.SpriteController.IsKeyPressed(Keys)"/>
/// </summary>
/// <example>
/// You want to define a variable on your form, something like:
///<code Lang="C#">
/// private KeyMessageFilter the_filter = new KeyMessageFilter();
///</code>
/// When the form loads (in the <see cref="System.Windows.Forms.Form.Load"/>
/// event of the form), set the filter with:
/// <code Lang="C#">
/// Application.AddMessageFilter(the_filter);
/// </code>
/// And then, to use it, do something like:
/// <code Lang="C#">
/// bool Up = m_filter.IsKeyPressed(Keys.W);
/// bool Down = m_filter.IsKeyPressed(Keys.S);
/// </code>
/// Much of this code was found here: <see href="http://stackoverflow.com/questions/1100285/how-to-detect-the-currently-pressed-key"/>
/// </example>
internal class KeyMessageFilter : IMessageFilter
{
private const int WM_KEYDOWN = 0x0100;
private const int WM_KEYUP = 0x0101;
private bool m_keyPressed = false;
public event SpriteKeyEventHandler KeyDown = delegate { };
public event SpriteKeyEventHandler KeyUp = delegate { };
private Dictionary<Keys, bool> m_keyTable = new Dictionary<Keys, bool>();
public Dictionary<Keys, bool> KeyTable
{
get { return m_keyTable; }
private set { m_keyTable = value; }
}
public bool IsKeyPressed()
{
return m_keyPressed;
}
public bool IsKeyPressed(Keys k)
{
bool pressed = false;
if (KeyTable.TryGetValue(k, out pressed))
{
return pressed;
}
return false;
}
public bool PreFilterMessage(ref Message m)
{
if (m.Msg == WM_KEYDOWN)
{
KeyTable[(Keys)m.WParam] = true;
KeyEventArgs e = new KeyEventArgs((Keys)m.WParam);
KeyDown(null, e);
m_keyPressed = true;
}
if (m.Msg == WM_KEYUP)
{
KeyTable[(Keys)m.WParam] = false;
KeyEventArgs e = new KeyEventArgs((Keys)m.WParam);
KeyUp(null, e);
m_keyPressed = false;
}
return false;
}
public List<Keys> KeysPressed()
{
var answer = KeyTable.Where(kvp => kvp.Value== true).Select(kvp => kvp.Key);
List<Keys> tList = new List<Keys>(answer);
return tList;
}
public void ResetState()
{
foreach (Keys key in KeyTable.Keys.ToList())
KeyTable[key] = false;
}
}
}